Hello and thank you for using HCM. I carefully read your question and I understand your little concern. But you have nothing to worry about. I compliment you for having the initiative to make yearly chek up. The right bundle branch block means a particular conduction of the electrical impulse in the heart. In a lot of cases it is a normal variant of your electrocardiogram pastern. This is frequently seen in young ages and doesn t mean any cardiac pathology. So, if you have done other examinations, like a echo cardiography and you don t have any complain we may say that we have nothing to worry about, this is quite normal. You can keep running without concern because it dosn t mean anything , you do not have any pathology, this is called a normal variant, like different eye colors. My opinion as cardiologist is to continue your normal live and keep training and doing your yearly chek up. Hope I was helpful. Wish you good health Best regards